Following heavy exposure to Mycobacterium tuberculosis (Mtb), a range of outcomes occurs including TB disease, asymptomatic or latent TB infection (TBI) defined clinically as a positive tuberculin skin test (TST) or IFNγ release assay (IGRA), and resistance to TST/IGRA conversion (RSTR) that may represent clearance of infection through IFNγ-independent mechanisms [2–4]. The gene discussed is IFNG; the disease is infection.